[ryall]

I don't understand why powered IoT devices (lightbulbs, switches etc) don't use powerline for network access.

[sidpatil]

Some of the pre-IoT home automation system did use powerline for communication: https://en.wikipedia.org/wiki/X10_(industry_standard)

[data-ottawa]

Would this be vulnerable to an adversary plugging a device into your exterior electrical outlets?

[froggit]

No. Powerline ethernet was pretty obviously going to have security issues along these lines from the go considering the lack of clear boundaries inherent in sending data over wires connecting to a public grid and included cryptography from the go. I know Homeplug devices have been on AES since the mid-2000s using either passwords or push button config and G.hn had something similar going on.

[plorg]

Back in the noughties plugging in a TV was enough to break some powerline ethernet.